Method for fabricating photomask

Abstract

Provided is a method for fabricating a photomask. The method includes the following processes. Light blocking patterns are formed on a mask substrate, and surface properties of the mask substrate on which the light blocking patterns are formed are changed into hydrophobicity. When the surface properties of the mask substrate are changed into the hydrophobicity, the mask substrate is treated using plasma gas. The plasma gas may be a gas mixture of trifluoromethane (CHF3), tetrafluoromethane (CF4), and hydrogen (H2).

What is claimed is: 
     
       1. A method for fabricating a photomask, the method comprising:
 forming light blocking patterns comprising chromium material on a quartz (Qz) substrate; and 
 performing a treatment process on an exposed surface of the quartz substrate to prevent an adsorption of contaminated molecules on the exposed surface of the quartz substrate by supplying plasma gas, wherein the plasma gas is a gas mixture of trifluoromethane (CHF 3 ), tetrafluoromethane (CF 4 ), and hydrogen (H 2 ), wherein a flow rate of the H 2  of the gas mixture is between 10 sccm and 29 sccm so that a tilt angle of a water molecule is between approximately 20° and 40° relative to the quartz substrate. 
 
     
     
       2. The method of  claim 1 , wherein the flow rate of the hydrogen (H 2 ) of the gas mixture is approximately 20 sccm so that the tilt angle of a water molecule relative to the quartz substrate is approximately 40°. 
     
     
       3. The method of  claim 1 , wherein the flow rate of the H 2  of the gas mixture is between 15 sccm and 25 sccm so that the tilt angle of a water molecule is between approximately 30° and 40° relative to the quartz substrate. 
     
     
       4. A method for fabricating a photomask, the method comprising:
 forming a phase shift layer on a quartz (Qz) substrate; 
 forming a light blocking layer on the phase shift layer; 
 patterning the light blocking layer and the phase shift layer; 
 removing the light blocking layer except that provided at a light blocking region; and 
 performing a treatment process on an exposed surface of the quartz substrate to prevent an adsorption of contaminated molecules on the exposed surface of the quartz substrate by supplying plasma gas, wherein the plasma gas is a gas mixture of trifluoromethane (CHF 3 ), tetrafluoromethane (CF 4 ), and hydrogen (H 2 ) , wherein a flow rate of the H 2  of the gas mixture is between 10 sccm and 29 sccm so that a tilt angle of a water molecule exceeds is between approximately 20° and 40° relative to the quartz substrate. 
 
     
     
       5. The method of  claim 4 , wherein the phase shift layer is formed using molybdenum silicon nitride (MoSiN). 
     
     
       6. The method of  claim 4 , wherein the light blocking layer is formed using chromium (Cr). 
     
     
       7. The method of  claim 4 , wherein the flow rate of the hydrogen (H 2 ) of the gas mixture is approximately 20 sccm so that the tilt angle of a water molecule relative to the quartz substrate is approximately 40 °. 
     
     
       8. The method of  claim 4 , wherein the flow rate of the H 2  of the gas mixture is between 15 sccm and 25 sccm so that the tilt angle of a water molecule is between approximately 30° and 40° relative to the quartz substrate.